The present invention relates to an oil supply and return tube system for oil tanks in cars, and more particularly to such an oil supply and return tube system which is suitable for use in any of a variety of cars.
FIG. 9 shows an oil supply and return tube system for oil tanks in cars according to U.S. Ser. No. 08/753,480. This system comprises a base 1 having two oil holes 14 (one for oil intake and one for oil return), two connectors 5 respectively fastened to the oil holes 14 by a screw joint, two rubber seal rings 51 respectively mounted around the connectors 5 to seal the gap. The oil pipe 6 which is to be connected to one oil hole 14 has a connector 61 at one end adapted for fastening to the connector 5 of the corresponding oil hole 14 by a screw joint. The drawback of this arrangement is that the oil seal rings 51 wear quick with use, thereby causing an oil leakage to occur. This oil supply and return tube system further comprises an air discharge valve 7 fastened to an air passage hole of the base 1 for adjustment of air pressure in the oil tank of the car. This structure of air discharge valve 7 comprises an air inlet hole 72 and an air outlet hole 73 connected in parallel to the air passage hole of the base 1, a cap 71 covered on the holes 72;73, a first spring 721 mounted inside the air inlet hole 72, a first stopper 722 supported on the first spring 721 and forced by it to close the passage of the air inlet hole 72, a second spring 731 mounted inside the air outlet hole 73, a second stopper 732 supported on the second spring 731 and forced by it to close the passage of the air outlet hole 73. The stoppers 722;732 are mounted with a respective copper plate 74. The size of the copper plates 74 for the stoppers 722;732 must be precisely controlled within a strict tolerance. If the copper plates 74 are made too large, they tend to damage the air discharge valve 7 when moved. If the copper plates 74 are made too small, they will be unable to stop the passage of the respective air holes.